\begin{tikzpicture}
  \tikzset{
    matrixstyle/.style={
      matrix of nodes, 
      nodes in empty cells, 
      matrix anchor=north west,
      nodes={draw, anchor=west, minimum height=2em, text width=12.5em}},
    rightarrow/.style={
      red, draw, single arrow, thick, scale=0.5,
      text width=0.5em, 
      anchor=west, rotate=0, xshift=0, fill=red},
  }
  \matrix [matrixstyle, matrix anchor=north west] at (n2.south west) (m1)
  {
    \node [align=center] {QT[q]}; & \node [align=center] {OBJ[p]};\\
    \node [rightarrow](n11){};\node [anchor=west]{\ \ (1)($+$ $a\rm (y)$ $b\rm (y)$ $t_1\rm (y)$)};&
    \textcircled{\footnotesize 1}LD $\rm R_0$,$a$\ \textcircled{\footnotesize 2}ADD $\rm R_0$, $b$\\
    \node [rightarrow](n21){};\node [anchor=west]{\ \ (2)($-$ $c\rm (y)$ $d\rm (y)$ $t_2\rm (y)$)};&
    \textcircled{\footnotesize 3}LD $\rm R_1$, $c$ \textcircled{\footnotesize 4}SUB $\rm R_1$, $d$\\
    \node [rightarrow](n31){};\node [anchor=west]{\ \ (3)($*$ $t_1\rm (y)$ $t_2\rm (n)$ $x\rm (y)$)};&
    \textcircled{\footnotesize 5}ST $\rm R_0$, $\rm R_2$ \textcircled{\footnotesize 6}MUL $\rm R_0$, $\rm R_1$\\
    \node [rightarrow](n41){};\node [anchor=west]{\ \ (4)($=$ $a\rm (y)$ \_  $y\rm (n)$)};&
    \textcircled{\footnotesize 7}LD $\rm R_1$, $a$\\
    \node [rightarrow](n51){};\node [anchor=west]{\ \ (5)($/$ $a\rm (n)$ $x\rm (n)$ $x\rm (y)$)};&
    \textcircled{\footnotesize 8}LD $\rm R_1$, $a$ \textcircled{\footnotesize 9}DIV $\rm R_1$, $\rm R_0$\\
    \node [rightarrow](n61){};\node [anchor=west]{\ \ (6)($-$ $a\rm (n)$ $x\rm (n)$ $x\rm (y)$)};&
    \textcircled{\footnotesize 10}ST $\rm R_1$, $\rm R_0$ \textcircled{\footnotesize 11}SUB $\rm R_1$, $t_1$\\
    \node [rightarrow](n71){};\node [anchor=west]{\ \ (7)($=$ $x\rm (y)$ \_ $a\rm (y)$)};&
    \textcircled{\footnotesize 12}ST $\rm R_0$, $\rm R_2$\\
    \node [rightarrow](n81){};\node [anchor=west]{\ \ (8)\ \ \ \ \ \ \ \ldots};&\\
  };
  \matrix [matrixstyle, matrix anchor=north west,nodes={draw, anchor=west, minimum height=2em, text width=1.5em},xshift=-.75em] at (m1.north east) (m2)
  {
    $\rm R_0$ & $\rm R_1$ & $\rm R_2$\\
    \node[minimum height=16.26em] {}; & \node[minimum height=16.26em] {}; & \node[minimum height=16.26em] {};\\
  };
  \node [anchor=north] at (m2-1-1.south) {\textcolor{red}{\bcancel{\textcolor{black}{$t_1$}}}};
  \node [anchor=north] at ([yshift=-2.5em]m2-1-2.south) {\textcolor{red}{\bcancel{\textcolor{black}{$t_2$}}}};
  \node [anchor=north] at ([yshift=-4.5em]m2-1-1.south) {\textcolor{red}{\bcancel{\textcolor{black}{$x$}}}};
  \node [anchor=north] at ([yshift=-4.5em]m2-1-3.south) {\textcolor{black}{$t_1$}};
  \node [anchor=north] at ([yshift=-6.5em]m2-1-2.south) {\textcolor{red}{\bcancel{\textcolor{black}{$y$}}}};
  \node [anchor=north] at ([yshift=-8.5em]m2-1-2.south) {\textcolor{red}{\bcancel{\textcolor{black}{$x$}}}};
  \node [anchor=north] at ([yshift=-10.5em]m2-1-1.south) {\textcolor{red}{\bcancel{\textcolor{black}{$x$}}}};
  \node [anchor=north] at ([yshift=-10.5em]m2-1-2.south) {\textcolor{black}{$y$}};
  \node [anchor=north] at ([yshift=-12.5em]m2-1-1.south) {\textcolor{black}{$a$}};
  \node [anchor=north] at ([yshift=-12.5em]m2-1-3.south) {\textcolor{black}{$x$}};
\end{tikzpicture}